Solvent impregnated resins for the removal of low concentration phenol from water

The focus of this investigation is the development of a solvent impregnated resin for phenol removal from dilute aqueous solutions. Using a solvent impregnated resin (SIR) eliminates the problem of emulsification encountered in liquid–liquid extraction. Impregnated MPP particles and impregnated XAD16 particles are successfully used for phenol extraction. Impregnated MPP particles are preferred, as impregnated XAD16 particles show less mechanical strength and are more expensive. Impregnated MPP particles perform better compared to other synthetic adsorbents and basic ion exchangers. The maximum phenol capacity of impregnated MPP particles with 0.99 mol Cyanex 923 kg-1 SIR is 4.1 mol kg-1 SIR (386 mg g-1 SIR) and of MPP particles containing 1.47 mol Cyanex 923 kg-1 SIR it is 5.08 mol kg-1 SIR (478 mg g-1 SIR). The regenerability of impregnated MPP particles is easy and complete, and the particles are stable during several cycles. The equilibrium constants for the extraction of phenol are determined as Kchem = 37 L mol-1 and Kphys = 18 (mol L-1) (mol L-1)-1. With these values the SIR isotherms can be satisfactorily described. The results indicate that SIR technology is a promising alternative for the conventional phenol removal technologies at low phenol concentration levels

Guidelines for solvent selection for carrier mediated extraction of proteins

Potentially, extraction techniques offer advantages such as higher capacity, better selectivity and integration between recovery and purification. Affinity extraction with organic solvents appears promising, provided that irreversible denaturation of the extracted biomolecules can be limited. Therefore, as a first essential step the influence of various organic solvents has been studied on the extraction of typical proteins (cytochrome c, myoglobin, human serum albumin HSA) and antibody (monoclonal Immunoglobulin G (IgG)) in liquid–liquid systems. For proteins, their conformation together with internal disulfide bonds give a picture of the predictable behaviour in contact with organic solvents. Depending on the type of protein the log P or the interfacial tension can give an indication about the overall stability. In the case of IgG existing solvents and selection methods used for small proteins are not suitable to define a good solvent for IgG free of stabilizers. However, when stabilizers and sugars are present in the buffer solution almost all the solvents tested show a good capacity to retain IgG concentration. Ionic liquids demonstrated a considerably higher capacity to retain the IgG concentration than conventional organic solvents, however, do not completely stabilize monoclonal IgG in pure solution